Protozoa Flashcards

Toxoplasma gondii - Ke Hu and John Murray

Protozoa

Question	Answer	Article
What are the four different ways protozoa can move?	Cilia Flagellum Pseduopodia Gliding	Link to Answer Article
How do protozoa reproduce?	By binary fission By schizogony By sporogony By gametogeny	Link to Answer Article
Briefly summarise the life cycle of protozoa	The infectious sporozoite are released from the oocyst invading epithelial tissue The nucleus of the sporozoites divides forming a schizont which contains merozoites (schizogony) Schizont ruptures releasing merozoites which form micro and macrogamonts in the epithelial tissue (gametogeny) Microgamonts penetrate the macrogamont forming the zygote The zygote forms the oocyst which is passed in the faeces Sporulation occurs which makes the oocyst infectious	Link to Answer Article

Coccidia

Question	Answer	Article
*What is the transmission and life cycle of Eimeria* species?**	Direct transmission Faecal-oral route	Link to Answer Article
*What is the transmission and life cycle of Isospora* species?**	Usually direct transmission by the faecal-oral route Some species use facultative intermediate hosts forming tissue cysts Transmission is then by the faecal-oral or route or via ingestion of the intermediate host	Link to Answer Article
*How long is the prepatent period of poultry Eimeria* species?**	1 week Sporulation takes 2-3 days	Link to Answer Article
*Name the malabsorptive Eimeria* species**	E. maxima E. acervulina E. mitis E. praecox	Link to Answer Article
*Name the haemorrhagic Eimeria* species**	E. necatrix E. brunetti E. tenella	Link to Answer Article
*Which area of the gastrointestinal tract does E. acervulina, E. maxima, E. tenella and E. necatrix affect and what kind of lesions are produced?*	E. acervulina affects the proximal gut forming white ladder lesions E. maxima affects the mid-gut producing a pink exudate E. tenella affects the ceaca forming a core of dark, haemorrhagic blood E. necatrix affects the mid-gut forming salt and pepper leions	Link to Answer Article
*What are the two main Eimeria* species which affect cattle and what is the prepatent period?**	E. zuernii E. bovis 2-3 week prepatent period	Link to Answer Article
*What are the two significant Eimeria* species which affect sheep and what is the prepatent period?**	E. ovinoidalis E. crandalis 2 week prepatent period	Link to Answer Article
*What is the most significant species of Isospora* which affects pigs and what the prepatent period?**	I. suis 1 week prepatent period	Link to Answer Article
*Which parts of the gastrointestinal tract do the Eimeria* species which affects rabbits inhabit?**	2 inhabit the caecum 1 inhabits the bile duct epithelium (E. steidae)	Link to Answer Article

Cryptosporidia

Question	Answer	Article
*What is the main species of Cryptosporidium* which infects humans and domestic animals?**	C. parvum	Link to Answer Article
*True or False: In Cryptosporidium* infections unsporulated oocysts are passed in the faeces**	False Sporulated oocysts are passed in the faeces	Link to Answer Article
*How are Cryptosporidium* infections passed between hosts?**	Direct faecal-oral transmission Water-bourne infections Autoinfection can also occur	Link to Answer Article
*How are Cryptosporidium* infections prevented?**	Isolate and quarantine brought in calves Good hygiene and adequate disinfection of calf pens Goog hygiene of humans working and visiting farms Halofuginone and other drug treatments	Link to Answer Article

Giardia

Question	Answer	Article
*What is the key points of the life cycle and prepatent period of Giardia?*	Simple life cycle Direct life cycle Reproduce by binary fission 5-6 day prepatent period	Link to Answer Article
*How do both people and animals become infected by Giardia?*	Water bourne transmission Direct faecal-oral transmission	Link to Answer Article
*How would you diagnose a Giardia* infection?**	The cysts are heavy and do not float well in saturated sodium chloride solution Cysts excretion is intermittent so faeces need to be collected and sampled over 3 days Cyst antigen can be detected in faeces by an immunoassay	Link to Answer Article

Piroplasmida

Question	Answer	Article
*True or False: Both trans-stadial and trans-ovarian transmission can occur in Babesia* species**	True	Link to Answer Article
*What are the recognisable features of small Babesia* species and give an example**	Peripheral nucleus Obtuse angle B. divergens	Link to Answer Article
*What are the recognisable features of large Babesia* species and give an example**	Central nucleus Acute angle B. major	Link to Answer Article
*What are the predisposing features to Babesia* infection?**	Susceptible animals introduced into an infected area Infected ticks introduced into a clean area Infected cattle introduced into an area with clean ticks Temporary reduction in the tick population decreasing the transmission rate (causing enzootic instability) Infected are transported or stressed in other ways, e.g. parturition	Link to Answer Article
*What are the different vectors for Babesia* species?**	Ixodes ricinus for B. divergens Haemaphysalis for B. major Boophilus for B. bovis and B. bigemina Dermacentor and Rhipicephalus for B. canis	Link to Answer Article
*What species are the natural vectors for Cytauxzoon?*	Ticks	Link to Answer Article
*Where do schizonts of Cytauxzoon felis* develop?**	In macrophages	Link to Answer Article
*What is the main condition caused by Theileria parva?*	East Coast Fever	Link to Answer Article
*What is the main condition caused by Theileria parva* and what is the intermediate host?**	East Coast Fever Rhipicephalus appendiculatus	Link to Answer Article
*What is the pathogenesis of Theileria parva* infections?**	Proliferation in the lymphoblasts Proliferation in the local lymph node followed by spread throughout the body Lymphocyte depletion	Link to Answer Article
*What are the clinical signs of Theileria parva* infection?**	Pyrexia Enlarged local lymph node Loss of condition	Link to Answer Article

Tissue Cyst Forming Coccidia

Question	Answer	Article
*What are the two main species of Neospora* of veterinary interest and which animals do they affect?**	N. caninum Dogs N. hughesi Horses	Link to Answer Article
*How long is the prepatent period of Neospora?*	5 days	Link to Answer Article
*What are the clinical signs of Neospora* infections in dogs?**	Ascending paralysis Sudden collapse due to myocarditis Muscle wasting	Link to Answer Article
*What are the clinical signs of Neospora* infections in cattle?**	Abortion Encephalomyelitis Paresis	Link to Answer Article
*What are the clinical signs of Neospora* infections in horses?**	Myeloencephalitis	Link to Answer Article
*How many intermediate and final hosts does Sarcocystis* have?**	One final host One intermediate host	Link to Answer Article
*True or False: Sarcocystis* infections are mainly asymptomatic**	True	Link to Answer Article
What is Equine protozoal myeloencephalitis?	Necrotising encephalomyelitis affecting the grey and white matter of the CNS Caused by S. neurona Causes spinal cord dysfunction leading to ataxia and paralysis	Link to Answer Article
*What is the most pathogenic species of Toxoplasma?*	T. gondii	Link to Answer Article
*True or False: The life cycle of Toxoplasma* is direct**	False The life cycle is complex Described as facultatively heterozygous	Link to Answer Article
*Describe the acute phase of Toxoplasma* infections**	*Asexual reproduction in the cell by endodyogeny (budding) producing 8-16 tachyzoites* Tachyzoites are released when host cell bursts Haematogenous spread as more cells are infected Infection continues until the animal develops immunity (around 2 weeks) at which point the infection enters the chronic phase	Link to Answer Article
*Describe the chronic phase of Toxoplasma* infections**	Slow growing intracellular bradyzoites become walled off forming infective cysts Bradyzoites are protected from the host immune response (whereas extracellular tachyzoites are killed) Cysts remain viable for months to years in muscle and nervous tissue If immunity is suppressed the infection can revert to the acute form	Link to Answer Article
*How can Toxoplasma* infections be prevented?**	ELISA to check for seropositive cats Humans can avoid oocyst ingestion Humans can avoid tissue cyst ingestion Sheep can be vaccinated or given medicated feed	Link to Answer Article

Tropical Protozoa

Question	Answer	Article
What species transmits Leishmania?	Sandflies Phlebotomus spp. in the Old World Lutzomyia spp. in the New World	Link to Answer Article
*Which cells are Leishmania* species intracellular parasites of?**	Macrophages	Link to Answer Article
*What are the clinical signs of Leishmania* infections?**	Cutaneous form Ulcers on the lips, eyelids and pinnae of ears Visceral form Eczema Fever Generalised lympadenopathy	Link to Answer Article
*How can you treat and prevent Leishmania* infections?**	Chemotherapy Prevent sandflies biting dogs through collars containing insecticides Destruction of infected and stray dogs	Link to Answer Article
*Which diseases so Trypanosome* species cause in cattle and in humans?**	Nagana in cattle (wasting disease) Chagas disease in humans, armadillos and possums Sleeping sickness in humans	Link to Answer Article
*Fill in the missing words about Leishmania* infections?**	Salivarian trypanosome species multiply in the proboscis and foregut of Tsetse flies. This is also known as anterior station development. Stercorian trypanosome species multiply in the hindgut of Triatomid bugs, keds and tabanids. This is also known as posterior station development.	Link to Answer Article
*What are the general clinical signs of Leishmania* infections?**	Anaemia Enlarged lymph nodes and spleen Degeneration and inflammation of multiple organs Loss of body condition Oedema of the limbs and genitalia in horses Myocarditis and corneal opacity in dogs and cats	Link to Answer Article
*How are Leishmania* infections diagnosed?**	Giemsa stained smears Fresh blood films looking for motile trypanosomes Haematocrit tubes looking for motile trypanosomes at the buffy coat/plasma interface	Link to Answer Article

Other Important Protozoa

Question	Answer	Article
*What is Balantidium* and where is it found?**	Ciliate protozoan Commensal organism Found in the lumen of the large intestine	Link to Answer Article